This invention relates to an improved hollow fiber membrane device in which a comparatively thin material surrounds and constrains a plurality of inner fibers assembled about a feed flow distribution means.
U.S. Pat. No. 3,339,341 describes a conventional hollow fiber membrane device in which a flexible, porous sleeve member encloses the fibers. Preferred is a circular knit fabric sleeve. This sleeve is used to facilitate insertion of the fiber bundle in the pressure vessel and to provide the desired reduction in cross-sectional area of the bundles during insertion.
U.S. Pat. No. 3,526,001 discloses the use of a flexible porous sleeve over a hollow fiber membrane bundle as an aid in handling.
U.S. Pat. No. 4,380,460 discloses a membrane device in which a slit tube surrounds the hollow fiber bundle, but this tube is expanded to contact the inner surface of the housing of said device. It follows that the slit tube does not greatly restrain movement of the hollow fibers. The slit tube is intended to shield the fiber bundle from scale and other debris on the housing inner surface.
U.S. Pat. No. 4,421,529 describes a method of operating intermittently membrane gas separation devices so as to reduce deterioration of performance. It is disclosed therein that a porous polymer outer wrap may be employed around the bundle to prevent shifting of the fibers. A DYNEL cloth outerwrap was used in the examples. DYNEL is a woven polyester fabric sold by Lamports Filter Media, Inc. of Cleveland, Ohio.
U.S. Pat. No. 3,690,465 describes a hollow fiber membrane device assembled about a porous polyolefin core which comprises thin layers of substantially parallel hollow fibers separated by thin foraminous materials which restrict movement of the fibers and prevent nesting. The presence of the foraminous material significantly reduces the volume productivity of such a device.
Hollow fiber membrane devices are used for selective separation of at least one fluid component from a mixture of fluids or a solution. Such devices generally comprise a plurality of hollow fiber membranes, said membranes being selectively permeable to at least one component of the fluid mixture. The hollow fiber membranes are disposed inside a housing. The housing has at least one inlet for bringing a fluid feed into contact with one surface of the hollow fiber membranes. A means to promote uniform distribution of the fluid feed is desirable. At least one outlet for discharge of the fluid which does not permeate through the membrane and at least one outlet for fluid which permeates through the membrane is also required. The hollow fibers are embedded in at least one tubesheet. The fiber bores communicate with the permeate outlet from the housing. The tubesheet sealingly engages the inner surface of the housing.